The karsts of Sulawesi Tenggara

The Sulawesi Tenggara karsts cover an area of around 5,000 km2 in the southeast of the island of Sulawesi, Indonesia. They include the 4 massifs of Matarombeo, Mekongga, Tangkelemboke and Sombori, an almost completely unexplored and forest covered mineral fortress, as well as the Labengki-Somborila archipelago, a group ofrocky islets and coral reefs, populated by fishing villages.

Scientific expedition on the island of Sulawesi in Indonesia
Unexplored and difficult to access, unstable terrain, endemic animals: the Matarombeo massif on the island of Sulawesi is the archetype par excellence of a “Lost World”.

Matarombeo massif

The Matarombeo karst covers an area of around 1,200 km2, roughly the size of the island of Martinique, with its eponymous peak reaching an altitude of around 1,500 metres. It is bordered to the north and south by two main rivers that flow from west to east along the entire length of the massif. These waterways offer the possibility of approaching the entire length of the massif and creating natural transects.

Almost entirely unexplored and difficult to access, the Matarombeo, Mekongga, Tangkelemboke and Sombori massifs protect no less than the largest intact primary forest in Sulawesi. They form a kind of“island within an island” of Sulawesi, a veritable sanctuary still relatively unspoiled.

What’s more, together with the adjacent Tangkelemboke, Mekkonga and Sombori massifs, southeast Sulawesi is still home to the island’s largest expanse of primary forest, one of the last bastions in the face of palm oil, pepper and cocoa plantations, cement factories and nickel mines.

As karst massifs are known to be the richest areas on the planet in terms of biodiversity, the almost total lack of knowledge about these massifs and the rivers that flow through them guarantees huge potential for discovery in terms of underground networks and species new to science.

The karsts of southeast Sulawesi among the islands of the Indonesian archipelago
The karsts of Sulawesi Tenggara among the islands of the Indonesian archipelago

The Sombori-Labengki archipelago

The above-mentioned karst massifs sink into the sea to the east at Matarape Bay, forming a multitude of rocky coves and islets reminiscent of many Southeast Asian tourist sites. The beauty of the area and the richness of the seabed have earned it the nickname of “little Raja Ampat “.

While the islands and coastline are dotted with a multitude of small villages that make their living mainly from artisanal fishing, the region is not spared by waste pollution, particularly plastic, and the unbridled exploitation of natural resources, including nickel, of which Sulawesi has some of the world’s largest reserves.

Sombori-Labengki archipelago, Indonesia
Sombori-Labengki archipelago, another form of “lost paradise”, where tourism development is only a matter of time. Will it be a tool for preservation, or the scourge of its destruction?

Further information

Find out more about our first conservation activities and our long-term strategy for preserving the karsts of Sulawesi Tenggara :